In the case of an internal combustion engine which has a cylinder fuel injection device, as a mode of fuel injection, two injection modes can be adopted, which are intake stroke injection to inject a fuel in an intake stroke, and compression stroke injection to inject a fuel in a compression stroke. However, each of the injection modes has its own merit and demerit. In the case of the intake stroke injection, such a merit is obtained that the temperature of the air which is taken into the cylinder is lowered by latent heat of vaporization at the time of the fuel being vaporized, and thereby, the charging efficiency of air can be enhanced. However, there is also the demerit that at a low-temperature time when the fuel is difficult to vaporize, the fuel which is injected into the cylinder in the intake stroke adheres to the cylinder wall, and is unburned and becomes HC and smoke to be discharged from the inside of the cylinder. Meanwhile, in the case of compression stroke injection, the fuel is injected into the atmosphere which reaches a high temperature due to compression, the fuel which adheres to the cylinder wall without being vaporized can be reduced, though the effect of enhancing the charging efficiency by the latent heat of vaporization cannot be obtained.
Japanese Patent Laid-Open No. 2005-061332 describes a specific example concerning the proper use of the respective injection modes having the merits and demerits as described above. According to the technique described in Japanese Patent Laid-Open No. 2005-061332, the compression stroke injection is selected for some time from the start of actuation, and after an integrated value of a fuel injection quantity or an integrated value of the number of times of fuel injection in the compression stroke injection reaches a threshold value, the injection mode is switched from the compression stroke injection to intake stroke injection. The aforementioned threshold value is an integrated value of a fuel injection quantity or an integrated value of the number of times of fuel injection which corresponds to a cylinder wall surface temperature when the cylinder is sufficiently warmed, and is set based on at least one of a cooling water temperature at the point of time of start of actuation, pressure of the fuel which is supplied to the fuel injection valve, and an engine stopping time.